package com.example.springboot.common;

import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.example.springboot.entity.User;
import com.example.springboot.exception.ServiceException;
import com.example.springboot.service.UserService;

import cn.hutool.core.util.StrUtil;
import jakarta.annotation.Resource;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
//在这里校验
public class JwtInterceptor implements HandlerInterceptor {

    @Resource
    private UserService userService;

    public boolean preHandle(HttpServletRequest request,HttpServletResponse response,Object handler){
        String token=request.getHeader("token");//header里面传过来的参数
        if(StrUtil.isBlank(token)){
            token=request.getParameter("token");//url参数?token=xxx
        }
        //如果不是映射到方法直接通过
        if(handler instanceof HandlerMethod){
            AuthAccess annotation=((HandlerMethod)handler).getMethodAnnotation(AuthAccess.class);
            if(annotation!=null){
                return true;
            }
        }
        //执行认证
        if(StrUtil.isBlank(token)){
            throw new ServiceException("401","请登录");
        }
        //获取token中的user Count
        String userCount;
        try{
            userCount=JWT.decode(token).getAudience().get(0);//JWT.decode(token)解码
        }catch(JWTDecodeException j){
            throw new ServiceException("401","请登录");
        }
        //根据token中的user count查询数据库
        User user=userService.selectByCount(userCount);
        if(user==null){
            throw new ServiceException("401","请登录");
        }
        //通过用户密码加密后生成一个验证器
        JWTVerifier jwtVerifier=JWT.require(Algorithm.HMAC256(user.getPwd())).build();
        try{
            jwtVerifier.verify(token);//验证token
        }catch(JWTVerificationException e){
            throw new ServiceException("401","请登录");
        }
        return true;
    }



}
